In recent years, along with a tendency to high brightness and whitening of a light-emitting diode element (chip), a light-emitting device employing a light-emitting diode element has been used for e.g. illumination or backlights for various displays or large-sized liquid crystal TVs. A support for mounting a light-emitting element on which a light-emitting diode element is to be mounted is usually required to have high reflection properties so that light emitted from the element is efficiently reflected. In addition, as the heat value is increased along with the tendency to high brightness of a light-emitting diode element in recent years and the temperature is excessively increased, a support from which heat generated from the light-emitting element is quickly dissipated and with which damages, etc. by heat can be suppressed and high reliability can be obtained, has been desired. Particularly in the case of a light-emitting device for e.g. illumination, it is necessary that a large quantity of heat generated from the light-emitting element is quickly dissipated to the outside.
As a support for mounting a light-emitting element to be used for such a light-emitting device, for example, a metal-resin package has been known (Patent Document 1).
A metal-resin package is one obtained by integrally forming a lead frame made of an electrically conductive metal such as aluminum, copper, an iron/copper alloy or an iron/nickel alloy and a filler-containing resin having a reflective filler dispersed in a resin. By mounting a light-emitting element on such a lead frame, heat generated from the light-emitting element is quickly dissipated. The filler-containing resin to be used for the metal-resin package has a great difference in the refractive index with the reflective filler and the resin, whereby a high reflectance can be obtained, and as its material cost is low, it has been widely used as a support for mounting a light-emitting element.
However, the metal-resin package is likely to be deteriorated by heat at its resin portion, and in a case where a high power light-emitting diode element (chip) is mounted, damage such as burning of the resin is likely to occur, thus leading to poor reliability as a light-emitting device. Particularly the resin portion of the metal-resin package is promptly damaged when irradiated with ultraviolet rays, and such a package is not applicable to a light-emitting device on which an ultraviolet LED is to be mounted as the light-emitting element.